* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  cursor: url("../assets/injection.png"), pointer;
}

body {
  min-height: 100vh;
  width: 100%;
  overflow: hidden;
}

body::before {
  content: "";
  display: block;
  position: fixed;
  width: 100%;
  min-height: 100vh;
  z-index: 1;
  background: url("../assets/bg.png") no-repeat;
  background-size: cover;
}

input + label {
  position: absolute;
  background: url("../assets/coronavirus.png") no-repeat center;
  background-position: center;
  height: 200px;
  width: 200px;
  left: -300px;
  display: block;
  z-index: 10;
  transform: translate(50%, -50%);
}

input:checked + label {
  opacity: 0;
  transition: all 0.5s;
  transform: rotate(120deg);
  transform-origin: 60%;
  z-index: -10;
}

.virus:nth-last-of-type(1) {
  animation: virusmove 5s linear 1s infinite;
  animation-direction: alternate;
}

.virus:nth-last-of-type(2) {
  animation: virusmove 8s linear 0.8s infinite;
  animation-direction: alternate;
}

.virus:nth-last-of-type(3) {
  animation: virusmove 10s linear 2s infinite;
  animation-direction: alternate;
}

.virus:nth-last-of-type(4) {
  animation: virusmove 15s linear 3s infinite;
  animation-direction: alternate;
}

.virus:nth-last-of-type(5) {
  animation: virusmove 20s linear 4s infinite;
  animation-direction: alternate;
}

.score {
  position: absolute;
  bottom: 0;
  height: 50px;
  line-height: 50px;
  font-size: 40px;
  font-size: bold;
  text-align: center;
  width: 100%;
  z-index: 5;
}

.score::after {
  content: counter(score);
  display: inline-block;
}

.score::before {
  content: "Kills : ";
  display: inline-block;
}

input:checked {
  counter-increment: score;
}

@keyframes virusmove {
  0% {
    left: 150%;
    top: 10%;
  }
  25% {
    left: 80%;
    top: 50%;
  }
  50% {
    left: 50%;
    top: 30%;
  }
  75% {
    left: 30%;
    top: 40%;
  }
  100% {
    left: -50%;
    top: 10%;
  }
}